1. Field of the Invention
The invention relates to composite screen or perforated surface and filtering membranes.
2. Related Art
Various gutter anti-clogging devices are known in the art and some are described in issued patents.
In my patent U.S. Pat. No. 6,598,352, incorporated herein by reference, I disclose a filter configuration comprised of a debris repelling membrane, overlying a skeletal structure of ellipsoid rods spaced and resting on vertical planes that serve to break the forward flow of water and to channel water onto and through its integral perforated horizontal plane. Included herein is product literature for LEAFFILTER™, a gutter guard patterned after designs disclosed in U.S. Pat. No. 6,598,352. To date, LEAFFILTER™ has been noted to remain free enough of debris clogs and/or coatings of scum, oil, and pollutants so as to disallow gutter clogs in every known instance of it's installation onto rain gutter systems attached to at least eight thousand residential homes. The LEAFFILTER™ system, however, is costly to manufacture in comparison to other gutter guard systems.
U.S. Pat. No. 6,463,700 to Davis teaches a composite gutter guard, marketed as Sheer Flo®, comprising a polymer coated fiberglass mesh filter cloth overlying and sonic  welded to an underlying perforated plane, disclosed in claims 1 and 4. Davis specifically teaches employment of a medium filter opening fiberglass mesh rather than a fine metal or polymer mesh cloth, disclosed in Column 1 lines 19-35. Such fiberglass mesh of medium openings can be shown to allow the lodging of pine needle tips and to be subject to water-proofing due to oil leaching from roofing shingles. This may cause permanent accumulation of debris upon the composite gutter guard and water-proofing may allow forward, rather than downward flow of water to occur. In instances of high ambient temperatures sonic welded fiberglass has been shown to break free of the underlying polymer plane and the composite gutter guard has been shown to warp and wave due to heat deformation. Davis teaches a mostly single planar composite gutter guard that allows much forward underflow of water to occur on the underside of the disclosed invention and such underflow acts to oppose downward flow of water through perforations.
U.S. Pat. No. 6,164,020 to Nitch teaches a gutter screen for preventing the accumulation of debris within a gutter. Nitch teaches a gutter screen that has a plurality of v-shaped bars positioned to run above and generally parallel to the gutter. Nitch teaches that the unique shape of the bars minimize the surface area of the underside of the screen decreases water tension on the underside of the screen and postulates that this decreases the ability of water to accumulate on the underside of the screen which promotes the pulling of water into the gutter, disclosed in Col. 2 lines 45 through 50. Such a device can be shown to eventually allow debris to accumulate within the spaces between v-shaped bars. Such a device can additionally be shown to allow the forward channeling of water to occur as an underflow from tip to tip of the downward most portion of the v-shaped bars due to their close spacing and lack of a length of downward extension that would provide a greater directed downward flow of water into the underlying gutter. This and other prior art do not recognize that water adhesion surfaces extending downward from a planar surface into a rain gutter in a height staggered manner or that are separated by a minimum of one inch provide greater siphoning action and are less likely to be overcome by a forward channeling of under flowing water on the underside of surfaces that receive water through perforations or open channels than is reliance on a lesser amount of water adhesion on the underside of perforated surfaces or screens with bottom most water dispersing areas  that are closely spaced and follow mostly horizontally linear or follow a linear path that angles downward from the rear most portion of a gutter guard to the front lip of a rain gutter. Allowing for greater spacing of rods or fins or water channeling paths or staggering and/or extending the height of rods or fins so that they extend to a depth that the volume of water they channel downward overcomes by sheer weight and gravity an opposing underflow and continues a downward flow into an underlying gutter has not been found to be a simple matter of anticipation, or design choice by those skilled in the arts. Rather, it has proved to be unclaimed in disclosed prior art and untested in the field with the exception of the LEAFFILTER™ gutter guard which has proved to be very efficient at channeling water downward into a rain gutter while disallowing either the rain gutter or the gutter guard to clog or exhibit an overflow of water. Nitch teaches that fine screens allow for water run-off and are less capable of receiving water than other structural components such as bars or ribs, disclosed in Col. I lines 33-35. This and other prior art such as U.S. Pat. No. 6,463,700 to Davis do not recognize that fine screens can be shown to exhibit great water permeability and downward water channeling properties when contacting ovaled or angled edged surfaces resting on downward extending legs as is disclosed in U.S. Pat. No. 6,598,352 to Higginbotham, Col. 18 lines 26-67, Col. 19 lines 1-54.
U.S. Pat. No. 5,755,061 to Chen teaches a rain cover that includes pairs of adjacent fins separated by a uniform traverse gap that significantly increases the return of water to the gutter by surface tension with the fin walls, disclosed in the ABSTRACT. As occurs with U.S. Pat. No. 6,164,020, copious amounts of roof runoff may negate the intended effect of water returning to the gutter allowing for forward flow of water past the gutter. The bottom terminal points of the fin walls Chen teaches exist in the same linear plane as do the bottom terminal points of the rods Nitch teaches in U.S. Pat. No. 6,164,020. This allows a forward underflow (beneath the topmost surface of a perforated or open channeled plane) of water to occur. In my U.S. Pat. No. 6,598,352 it is disclosed that such forward rather than downward flow of water has been shown to cease if downward extending planes or rods of varying heights, disallowing a linear channeling path for water to follow, and sufficiently spaced are employed beneath the top most surface of  water receiving areas but the disclosed preferred embodiment has been shown costly to manufacture.
U.S. Pat. No. 5,557,891 to Albracht teaches a gutter protection system for preventing entrance of debris into a rain gutter. Albracht teaches a gutter protection system to include a single continuous two sided well with angled sides and perforated bottom shelf 9 into which rainwater will flow and empty into the rain gutter below. The well is of a depth, which is capable of receiving a filter mesh material. However, attempts to insert or cover such open channels of “reverse-curve” devices with filter meshes or cloths is known to prevent rainwater from entering the water receiving channels. This occurrence exists because of the tendency of such membranes, (unsupported by a proper skeletal structure), to channel water, by means of water adhesion along the interconnected paths existing in the filter membranes (and in the enclosures they may be contained by or in), past the intended water-receiving channel and to the ground. This occurrence also exists because of the tendency of filter mediums of any present known design or structure to quickly waterproof or clog when inserted into such channels creating even greater channeling of rainwater forward into a spill past an underlying rain gutter. Filtering of such open, recessed, channels existing in Albracht's invention as well as in U.S. Pat. No. 5,010,696, to Knittel, U.S. Pat. No. 2,672,832 to Goetz, U.S. Pat. Nos. 5,459,965 & 5,181,350 to Meckstroth, U.S. Pat. No. 5,491,998 to Hansen, U.S. Pat No. 4,757,649 to Vahldieck and in similar “reverse-curved” inventions that rely on “reverse-curved” surfaces channeling water into an open channel have been known to disallow entrance of rainwater into the water-receiving channels. Albracht's as well as previous and succeeding similar inventions have therefore notably avoided the utilization of filter insertions. What may appear as a logical anticipation by such inventions at first glance, (inserting of a filter mesh or material into the channel), has been shown to be undesirable and ineffective across a broad spectrum of filtering materials: Employing insertable filters into such inventions has not been found to be a simple matter of anticipation, or design choice of filter medium by those skilled in the arts. Rather, it has proved to be an ineffective option, with any known filter medium, when attempted in the field. Such attempts, in the field, have demonstrated that the filter mediums will eventually require manual cleaning. 
German Patent 5,905,961 teaches a gutter protection system for preventing the entrance of debris into a rain gutter. The German patent teaches a gutter protection system to include a single continuous two sided well 7 with angled sides and perforated bottom shelf which rainwater will flow and empty into the rain gutter below. The well is recessed beneath and between two solid lateral same plane shelves close to the front of the system for water passage near and nearly level with the front top lip of the gutter. The well is of a depth, which is capable of receiving a filter mesh material. However, for the reasons described in the preceding paragraphs, an ability to attach a medium to an invention, not specifically designed to utilize such a medium, may not result in an effective anticipation by an invention. Rather, the result may be a diminishing of the invention and its improvements as is the case in Albracht's patent 5,557,891, the German Patent, and similar inventions employing recessed wells or channels between adjoining planes or curvatures.
U.S. Pat. No. 5,595,027 to Vail teaches a continuous opening 24A between the two top shelves. Vail teaches a gutter protection system having a single continuous well 25, the well having a depth allowing insertion and retention of filter mesh material 26 (a top portion of the filler mesh material capable of being fully exposed at the holes). Vail does teach a gutter protection system designed to incorporate an insertable filter material into a recessed well. However, Vail notably names and intends the filter medium to be a tangled mesh fiberglass five times the thickness of the invention body. This type of filtration medium, also claimed in U.S. Pat. No. 4,841,686 to Rees, and in prior art currently marketed as FLO-FREE™ is known to trap and hold debris within itself which, by design, most filter mediums are intended to do, i.e.: trap and hold debris. Vail's invention does initially prevent some debris from entering an underlying rain gutter but gradually becomes ineffective at channeling water into a rain gutter due to the propensity of their claimed filter mediums to clog with debris. Though Vail's invention embodies an insertable filter, such filter is not readily accessible for cleaning when such cleaning is necessitated. The gutter cover must be removed and uplifted for cleaning and, the filter medium is not easily and readily inserted replaced into its longitudinal containing channel extending three or more feet. It is often noted, in the field, that these and similar inventions hold fast pine needles in great numbers which presents an unsightly  appearance as well as create debris dams behind the upwardly extended and trapped pine needles. Such filter meshes and non-woven lofty fiber mesh materials, even when composed of finer micro-porous materials, additionally tend to clog and fill with oak tassels and other smaller organic debris because they are not resting, by design, on a skeletal structure that encourages greater water flow through its overlying filter membrane than exists when such filter meshes or membranes contact planar continuously-connected surfaces. Known filter mediums of larger openings tend to trap and hold debris. Known filter mediums smaller openings clog or “heal over” with pollen and dirt that becomes embedded and remains in the finer micro-porous filter mediums. There had not been found, as a matter of common knowledge or anticipation, an effective water-permeable, non-clogging “medium-of-choice” that can be chosen, in lieu of claimed or illustrated filter mediums in prior art, that is able to overcome the inherent tendencies of any known filter mediums to clog when applied to or inserted within the types of water receiving wells and channels noted in prior art until such a medium of inter connected centered threads was disclosed in my U.S. Pat. No. 6,598,352 Col. 22 lines 47-50. The present invention will employ such medium and utilize such in an embodiment less costly to manufacture while remaining effective.
Vail also discloses that filter mesh material 26 is recessed beneath a planar surface that utilizes perforations in the plane to direct water to the filter medium beneath. Such perforated planar surfaces as utilized by Vail, by Sweers U.S. Pat. No. 5,555,680, by Morin U.S. Pat. No. 5,842,311 and by similar prior art are known to only be partially effective at channeling water downward through the open apertures rather than forward across the body of the invention and to the ground. This occurs because of the principal of water adhesion: rainwater tends to flow around perforations as much as downward through them, and miss the rain gutter entirely. Also, in observing perforated planes such as utilized by Vail and similar inventions (where rainwater experiences its first contact with a perforated plane) it is apparent that they present much surface area impervious to downward water flow disallowing such inventions from receiving much of the rainwater contacting them. 
A simple design choice or anticipation of multiplying the perforations can result in a weakened body subject to deformity when exposed to the weight of snow and/or debris or when, in the case of polymer bodies, exposed to summer temperatures and sunlight.
U.S. Pat. No. 5,406,754 to Cosby teaches a gutter guard comprising a fine screen supported by a structural stiffening matrix support that prevents the penetration of even fine debris from entering a gutter. When lesser amounts of water flow are present such a device will allow water flow through its combination of screens downward into the gutter. However, during heavy rainfall, roof runoff is known to simply travel over the top most surface of such a device past an underlying gutter rather that downward into the gutter. As with other devices aforementioned in preceding paragraphs, this may occur due to a forward moving underflow of water that can occur beneath the top most surface of nearly planar gutter guards that do not incorporate downward extending planes that break forward flow of water.
U.S. Pat. No. 4,841,686 to Rees teaches an improvement for rain gutters comprising a filter attachment, which is constructed to fit over the open end of a gutter. The filter attachment comprised an elongated screen to the underside of which is clamped a fibrous material such as fiberglass. Rees teaches in the Background of The Invention that many devices, such as slotted or perforated metal sheets, or screens of wire or other material, or plastic foam, have been used in prior art to cover the open tops of gutters to filter out foreign material. He states that success with such devices has been limited because small debris and pine needles still may enter through them into a rain gutter and clog its downspout opening and or lodge in and clog the devices themselves. Rees teaches that his use of a finer opening tangled fiberglass filter sandwiched between two lateral screens will eliminate such clogging of the device by smaller debris. However, in practice it is known that such devices as is disclosed by Rees are only partially effective at shedding debris while channeling rainwater into an underlying gutter. Shingle oil leaching off of certain roof coverings, pollen, dust, dirt, and other fine debris are known to “heal over” such devices clogging and/or effectively “water-proofing” them and necessitate the manual cleaning they  seek to eliminate. (If not because of the larger debris, because of the fine debris and pollutants). Additionally, again as with other prior art that seeks to employ filter medium screening of debris; the filter medium utilized by Rees rests on an inter-connected planar surface which provides non-broken continuous paths over and under which water will flow, by means of water adhesion, to the front of a gutter and spill to the ground rather than drop downward into an underlying rain gutter. Whether filter medium is “sandwiched” between perforated planes or screens as in Rees' invention, or such filter medium exists below perforated planes or screens and is contained in a well or channel, water will tend to flow forward along continuous paths through cur as well as downward into an underlying rain gutter achieving less than desirable water-channeling into a rain gutter.
U.S. Pat. No. 5,956,904 to Gentry teaches a first fine screen having mesh openings affixed to an underlying screen of larger openings. Both screens are elastically deformable to permit a user to compress the invention for insertion into a rain gutter. Gentry, as Rees, recognizes the inability of prior art to prevent entrance of finer debris into a rain gutter, and Gentry, as Rees, relies on a much finer screen mesh than is employed by prior art to achieve prevention of finer debris entrance into a rain gutter. In both the Gentry and Rees prior art, and their improvements over less effective filter mediums of previous prior art, it becomes apparent that anticipation of improved filter medium or configurations is not viewed as a matter of simple anticipation of prior art which has, or could, employ filter medium. It becomes apparent that improved filtering methods may be viewed as patentable unique inventions in and of themselves and not necessarily an anticipation or matter of design choice of a better filter medium or method being applied to or substituted within prior art that does or could employ filter medium. However, though Rees and Gentry did achieve finer filtration over filter medium utilized in prior art, their inventions also exhibit a tendency to channel water past an underlying gutter and/or to heal over with finer dirt, pollen, and other pollutants and clog thereby requiring manual cleaning. Additionally, when filter medium is applied to or rested upon planar perforated or screen meshed surfaces, there is a notable tendency for the underlying perforated plane or screen to channel water past the gutter where it will then spill to the ground. It has also been noted that prior art listed herein exhibits a tendency to allow filter cloth mediums to sag into the opening of their underlying  supporting structures. To compensate for forward channeling of water, prior art embodies open apertures spaced too distantly, or allows the apertures themselves to encompass too large an area, thereby allowing the sagging of overlying filter membranes and cloths. Such sagging creates pockets wherein debris tends to settle and enmesh.
U.S. Pat. No. 3,855,132 to Dugan teaches a porous solid material which is installed in the gutter to form an upper barrier surface (against debris entrance into a rain gutter). Though Dugan anticipates that any debris gathered on the upper barrier surface will dry and blow away, that is not always the case with this or similar devices. In practice, such devices are known to “heal over” with pollen, oil, and other pollutants and effectively waterproof or clog the device rendering it ineffective in that they prevent both debris and water from entering a rain gutter. Pollen may actually cement debris to the top surface of such devices and fail to allow wash-off even after repeated rains. U.S. Pat. No. 4,949,514 to Weller sought to present more water receiving top surface of a similar solid porous device by undulating the top surface but, in fact, effectively created debris “traps” with the peak and valley undulation. As with other prior art, such devices may work effectively for a period of time but tend to eventually channel water past a rain gutter, due to eventual clogging of the device itself.
There are several commercial filtering products designed to prevent foreign matter buildup in gutters. For example the FLO-FREE™ gutter protection system sold by DCI of Clifton Heights, Pa. comprises a 0.75-inch thick nylon mesh material designed to fit within 5-inch K-type gutters to seal the gutters and downspout systems from debris and snow buildup. The FLO-FREE™ device fits over the hanging brackets of the gutters and one side extends to the bottom of the gutter to prevent the collapse into the gutter. However, as in other filtering attempts, shingle material and pine needles can become trapped in the coarse nylon mesh and must be periodically cleaned.
U.S. Pat. No. 6,134,843 to Tregear teaches a gutter device that has an elongated matting having a plurality of open cones arranged in transverse and longitudinal rows, the base of the cones defining a lower first plane and the apexes of the cones defining an upper second plane Col. 5 lines 16-25. Although the Tregear device overcomes the eventual  trapping of larger debris within a filtering mesh composed of fabric sufficiently smooth to prevent the trapping of debris he notes in prior art, the Tregear device tends to eventually allow pollen, oil which may leach from asphalt shingles, oak tassels, and finer seeds and debris to coat and heal over a top-most matting screen it employs to disallow larger debris from becoming entangled in the larger aperatured filtering medium it covers. Filtering mediums (exhibiting tightly woven, knitted, or tangled mesh threads to achieve density or “smoothness”) disclosed in Tregear and other prior art have been unable to achieve imperviousness to waterproofing and clogging effects caused by a healing or pasting over of such surfaces by pollen, fine dirt, scum, oils, and air and water pollutants. Tregear indicates that filtered configurations such as a commercially available attic ventilation system known as Roll Vent® manufactured by Benjamin Obdyke, Inc. Warminster, Pa. is suitable, with modifications that accommodate its fitting into a rain gutter. However, such a device has been noted, even in its original intended application, to require cleaning (as do most attic screens and filters) to remove dust, dirt, and pollen that combine with moisture to form adhesive coatings that can scum or heal over such attic filters. Additionally, referring again to Tregear's device, a lower first plane tends to channel water toward the front lip of a rain gutter, rather than allowing it's free passage downward, and allow the feeding and spilling of water up and over the front lip of a rain gutter by means of water-adhesion channels created in the lower first plane.
Prior art has employed filter cloths over underlying mesh, screens, cones, longitudinal rods, however such prior art has eventually been realized as unable to prevent an eventual clogging of their finer filtering membranes by pollen, dirt, oak tassels, and finer debris. Such prior art has been noted to succumb to eventual clogging by the healing over of debris which adheres itself to surfaces when intermingled with organic oils, oily pollen, and shingle oil that act as an adhesive. The hoped for cleaning of leaves, pine needles, seed pods and other debris by water flow or wind, envisioned by Tregear and other prior art, is often not realized due to their adherence to surfaces by pollen, oils, pollutants, and silica dusts and water mists. The cleaning of adhesive oils, fine dirt, and particularly of the scum and paste formed by pollen and silica dust (common in many soil types) by flowing water or wind is almost never realized in prior art. 
Prior art that has relied on reverse curved surfaces channeling water inside a rain gutter due to surface tension, of varied configurations and pluralities, arranged longitudinally, have been noted to lose their surface tension feature as pollen, oil, scum, eventually adhere to them. Additionally, multi-channeled embodiments of longitudinal reverse curve prior art have been noted to allow their water receiving channels to become packed with pine needles, oak tassels, other debris, and eventually clog disallowing the free passage of water into a rain gutter. Examples of such prior art are seen in various other commercially available products. In one such product, dirt and mildew build up on the bull-nose of the curve preventing water from entering the gutter. Other such products are similarly noted to lose their water-channeling properties due to dirt buildup. These commercial products state such, in literature to homeowners that advises them on the proper method of cleaning and maintaining their products.
None of theses above-described systems keep all debris out of a gutter system allowing water alone to enter, for an extended length of time. Some allow lodging and embedding of pine needles and other debris within their open water receiving areas causing them to channel water past a rain gutter. Others allow such debris to enter and clog a rain gutter's downspout opening. Still others, particularly those employing filter membranes, succumb to a paste and or scum-like healing over and clogging of their filtration membranes over time rendering them unable to channel water into a rain gutter. Pollen and silica dirt, particularly, are noted to cement even larger debris to the filter, screen, mesh, perforated opening, and/or reverse curved surfaces of prior art, adhering debris to prior art in a manner that was not envisioned. 